$A$ body is moving along a horizontal surface with a velocity of $4 \,m/s$. If the coefficient of kinetic friction is $0.2$, the distance travelled by the body before coming to rest is $(g = 10 \,m/s^2)$. (in $\,m$)

What is rolling friction? Write the laws of rolling friction. Define the coefficient of rolling friction.

$A$ block is projected with speed $20 \,m/s$ on a rough horizontal surface. The coefficient of friction $(\mu)$ between the surfaces varies with time $(t)$ as shown in the figure. The speed of the body at the end of $4 \,s$ will be ............ $m/s$ $(g = 10 \,m/s^2)$.

When we rub our palms,they get heated,but only up to a maximum temperature because:

$A$ block of $7\,kg$ is placed on a rough horizontal surface and is pulled by a variable force $F$ (in $N$) $= 5t$,where $t$ is time in seconds,at an angle of $37^{\circ}$ with the horizontal as shown in the figure. The coefficient of static friction between the block and the surface is $\mu = 1$. If the force starts acting at $t = 0\,s$,find the time at which the block starts to slide. (Take $g = 10\,m/s^2$)

Calculate the stopping distance of a vehicle of mass $M$ moving with velocity $v$ on a straight road. (Where $\mu$ is the coefficient of friction between the tires and the road.)